140 / 258
1662
Butler-Thompson et al.:
J
ournal of
AOAC I
nternational
V
ol.
98, N
o.
6, 2015
acceptable since repeatability only exceeded the requirement by
1–2%, and all of the products that exceeded the reproducibility
requirement except one were near or below the minimum SMPR
reproducibility level of 0.3 µg/100 g RTF liquid.
Several laboratories provided comments about the method.
Some laboratories noted that they did not always know how
much vitamin B
12
was in the samples that they were testing, so it
was hard to know how much filtrate to load onto the solid-phase
extraction cartridge. Some laboratories had safety concerns
about working with potassium cyanide, and another laboratory
asked for a procedure to check SPE cartridge efficiency and
vitamin B
12
recovery. To address these concerns, a safety section
and an SPE cartridge qualification procedure were added to the
Final Action method.
Conclusions
AOAC Method
2011.10
was collaboratively studied by
nine to 11 laboratories from eight different countries with a
variety of infant, pediatric, and adult matrixes. Per the AOAC
ERP, the method demonstrated acceptable repeatability and
reproducibility and met the SPIFAN SMPR for the majority
of product matrixes analyzed. Although repeatability and
reproducibility for some product matrixes exceeded the
requirements in SMPR 2011.005, it was the majority opinion
of the ERP that these results were acceptable since repeatability
only exceeded the requirement by 1–2%, and all of the products
that exceeded the reproducibility requirement except one
were near or below the minimum SMPR reproducibility level
of 0.3 µg/100 g RTF liquid.
Figure 2011.10E. Typical sample chromatogram.
Figure 2011.10D. Typical standard chromatogram.
140